panic: witness_warn Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *175334 82294 0 0 0x4000000 0 syz-executor7144 427036 84602 0 0 0x480 1 syz-executor7144 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399 panic() at panic+0x16c sys/kern/subr_prf.c:208 witness_warn(15552fc2a820bb84,0,ffff800020b74bc0) at witness_warn+0x6e0 witness_debugger sys/kern/subr_witness.c:2546 [inline] witness_warn(15552fc2a820bb84,0,ffff800020b74bc0) at witness_warn+0x6e0 sys/kern/subr_witness.c:1462 userret(9e8bd6e5bda8e078) at userret+0x361 sys/kern/kern_sig.c:1899 syscall(5f1f968ae6d3bfd6) at syscall+0x680 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(5f1f968ae6d3bfd6) at syscall+0x680 sys/arch/amd64/amd64/trap.c:605 Xsyscall(6,5,de66d540c8,0,de66d540a8,de66d540a0) at Xsyscall+0x128 end of kernel end trace frame: 0xe0be6e8510, count: 9 https://www.openbsd.org/ddb.html describes the minimum info required in bug reports. Insufficient info makes it difficult to find and fix bugs. ddb{0}> ddb{0}> set $lines = 0 ddb{0}> show panic witness_warn ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399 panic() at panic+0x16c sys/kern/subr_prf.c:208 witness_warn(15552fc2a820bb84,0,ffff800020b74bc0) at witness_warn+0x6e0 witness_debugger sys/kern/subr_witness.c:2546 [inline] witness_warn(15552fc2a820bb84,0,ffff800020b74bc0) at witness_warn+0x6e0 sys/kern/subr_witness.c:1462 userret(9e8bd6e5bda8e078) at userret+0x361 sys/kern/kern_sig.c:1899 syscall(5f1f968ae6d3bfd6) at syscall+0x680 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(5f1f968ae6d3bfd6) at syscall+0x680 sys/arch/amd64/amd64/trap.c:605 Xsyscall(6,5,de66d540c8,0,de66d540a8,de66d540a0) at Xsyscall+0x128 end of kernel end trace frame: 0xe0be6e8510, count: -6 ddb{0}> show registers rdi 0 rsi 0x1 rbp 0xffff800020c1d5b0 rbx 0xffff800020c1d650 rdx 0xffffffff81ec577a cmd0646_9_tim_udma+0x16395 rcx 0x201 rax 0x1 r8 0xffffffff81788154 kprintf+0x174 r9 0x1 r10 0xdb67ae6ff8eaa839 r11 0x4b9cb1f45b0a2212 r12 0x3000000008 r13 0xffff800020c1d5c0 r14 0x100 r15 0x1 rip 0xffffffff81107618 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020c1d5a0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor7144) pid=175334 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff800020b75520,0xffff800020b75080 process=0xffff800020bcb080 user=0xffff800020c18000, vmspace=0xfffffd806e9372d8 estcpu=36, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 82294 427157 84602 0 2 0 syz-executor7144 *82294 175334 84602 0 7 0x4000000 syz-executor7144 82294 61176 84602 0 3 0x4000080 fsleep syz-executor7144 82294 223855 84602 0 2 0x4000000 syz-executor7144 88069 244345 82639 0 2 0 syz-executor7144 88069 495463 82639 0 3 0x4000080 fsleep syz-executor7144 84602 427036 15882 0 7 0x480 syz-executor7144 82639 478770 15882 0 2 0 syz-executor7144 15882 208260 3018 0 3 0x82 nanosleep syz-executor7144 3018 94359 9945 0 3 0x10008a pause ksh 9945 133407 20061 0 3 0x92 select sshd 98405 81664 1 0 3 0x100083 ttyin getty 20061 165613 1 0 3 0x80 select sshd 64247 199513 82139 73 3 0x100010 ffs_fsync syslogd 82139 3779 1 0 3 0x100082 netio syslogd 27317 186814 1 77 3 0x100090 poll dhclient 9549 212121 1 0 3 0x80 poll dhclient 90711 404011 0 0 3 0x14200 pgzero zerothread 54608 393432 0 0 3 0x14200 aiodoned aiodoned 59075 434843 0 0 3 0x14200 syncer update 98599 508448 0 0 3 0x14200 cleaner cleaner 79588 9890 0 0 3 0x14200 reaper reaper 63835 189396 0 0 3 0x14200 pgdaemon pagedaemon 94940 521017 0 0 3 0x14200 bored crynlk 43936 46918 0 0 3 0x14200 bored crypto 92037 504466 0 0 3 0x40014200 acpi0 acpi0 48252 303887 0 0 3 0x40014200 idle1 6935 419957 0 0 3 0x14200 bored softnet 31917 341682 0 0 3 0x14200 bored systqmp 76968 385231 0 0 3 0x14200 bored systq 26928 182055 0 0 3 0x40014200 bored softclock 10636 485841 0 0 3 0x40014200 idle0 1 61555 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper